Variable speed transmission



June 5, 1956 2. v. WEISEL 2,748,614

VARIABLE SPEED TRANSMISSION Filed June 25, 1955 6 Sheets-Sheet 1 BY WgMJammy June 5, 1956 2. v. WEISEL 2,748,614

VARIABLE SPEED TRANSMISSION Filed June 23, 1953 6 Sheets-Sheet 2 IN V ENTOR. [Z /v45 K #2755;

June 5, 1956 z. v. WEISEL 2,748,614

VARIABLE SPEED TRANSMISSION Filed June 23, 1955 s Sheets- Sheet 5 on.INLET TO 5uMP IN V EN TOR. [EA/4.5 7127551.

June 5, 1956 z, y, w s 2,748,614

VARIABLE SPEED TRANSMISSION Filed June 25, 1953 6 Sheets-Sheet 4 fit!INVENTOR.

Z e/vns K IKE/55L Jttornfj/s June 5, 1956 2. v. WEISEL VARIABLE SPEEDTRANSMISSION 6 Sheets-Sheet 5 Filed June 23, 1953 INVENTOR. Zs/ms MWE/sa Jaw Wghw ufltarne .5

June 5, 1956 2. v. WEISEL 2,748,614

VARIABLE SPEED TRANSMISSION Filed June 23, 1953 6 Sheets-Sheet 6 INVENTOR. ZEMQS Z 14 5/5154 United States Patent VARIABLE SPEED TRANSMISSIONZenas V. Weisel, Los Angeles, Calif.

Application June 23, 1953, Serial No. 363,606

11 Claims. (Cl. 74-200) The present invention relates generally totransmissions and more particularly to an improved high speedtransmission especially suitable for use in aircraft.

Modernly, there exists a need for a transmission adapted to connect apower source having a variable speed to a driven member which mustrotate at a substantially constant speed despite variations in the loadimposed thereon. One example lies in the driving of aircraftalternators. If a transmission is to be used in aircraft, it mustadditionally be light in weight, compact, and foolproof. Moreover, itmust be capable of transmitting a high percentage of driving power intouseful work over the wide speed range at which the power source mayrotate. The primary purpose of the present invention is to provide anovel transmission embodying all of these qualities.

A major object of the present invention is to provide an improved highspeed continuous, variable ratio transmission.

It is a further object of the present invention to provide atransmission incorporating complementary driving and driven discsdefining opposed surfaces of revolution, which discs are bridged by oneor more power-transmitting, comically-profiled rollers.

Another object is to provide a transmission of this nature which is veryeflicient at all speeds and under all load conditions.

It is yet another object to provide a transmission of this type whereinvariation in the relative speeds of the discs can be infinitelycontrolled within maximum and minimum limits by changing the angularityof the bridging rollers relative to the discs; such rollers beingmounted and controlled in a novel manner whereby they will follow aspiral path in moving from one position to another; and such rollersbeing so mounted and controlled that the traction forces have notendency to change the angularity of the rollers.

Yet another object is to provide a transmission of this nature whichwill quickly and smoothly respond to any change in speed of the discs.

It is a still further object of the invention to provide a transmissionof this nature incorporating improved integral air cooling for thedriving and driven discs, as well as for the rollers; and to provide animproved lubrication system for such discs and rollers.

A11 additional object of the invention is to provide a transmission ofthis nature having novel means for mounting the rollers.

it is yet a further object of the present invention to provide a noveltransmission of this nature having novel means for preventing slippagebetween the discs and the rollers.

Another object is to provide a transmission of this nature whereintracking of the rollers on the discs is insensitive to deflections,differential expansion, tolerance variations in machining and tovariations in power load;

Yet an additional object of the invention is to provide a transmissionwhich is very compact and yet is capable ice of transmitting a largeload over an extended period of time without requiring attention.

A further object is to provide a transmission utilizing wide-facedconoidal rollers which require the minimum rol'ler-to-disc loading forcerelative to traction force.

These and other objects and advantages of the present invention willbecome apparent from the following detailed description when taken inconjunction with the appended drawings wherein:

Figure 1 is a longitudinal vertical sectional view of a transmissionembodying the present invention and including the air cooling systemthereof;

Figure 2 is a reduced transverse vertical sectional view of saidtransmission showing the air cooling system and roller mounting thereof;7

Figure 3 is an elevational view of the input side of said transmission;

Figure 4 is an elevational view of the input side of the driving discmember of said transmission;

Figure 5 is an enlarged fragmentary detail taken approximately on theline VV of Figure 4;

Figure 6 is an enlarged fragmentary detail taken on line VIVI of Figure4;

Figure 7 is a longitudinal vertical sectional view through atransmission generally similar to that shown in Figure 1, illustrating aform of lubricating system which may be utilized therewith;

Figure 8 is an enlarged sectional view of an alternate form of rollermounting;

Figure'9 is a longitudinal sectional view of another form oftransmission embodying the present invention;

Figure 10 is a vertical sectional view illustrating the roller mountingutilized in the transmission of Figure 9;

Figure 11 is a fragmentary vertical sectional view taken on line XI-XIof Figure 9;

Figure 12 is an enlarged vertical sectional view of a detail of Figure9;

Figure 13 is a fragmentary enlarged view of the en circled portionXIIIXIII of Figure 9;

Figure 14 is an exploded and enlarged view of a variable torque controldevice utilized with the transmission shown in Figure 9;

Figure 15 is an enlarged horizontal sectional view taken on line XVXV ofFigure 14;

Figure 16 is a sectional view taken on line XVIXVI of Figure 14;

Figure 17 is a perspective view of a scooping finger utilized in thetorque control device of Figure 14;-

Figure' 18 is a view similar to Figure 14, but showing another type ofvariable torque control device which may be utilized with thetransmission shown in Figure 9; and

Figure 19is a reduced vertical sectional view taken on line XIX-XIX ofFigure 18.

Referring to the drawings, and in particular, to Figure 1 thereof, thereis shown a right-hand end plate 10 having a frusto-conical portion 12with a bearing flange 14 extending inwardly therefrom. The flange 14supports a ball bearing assembly 16, and this bearing assembly rotatablysupports a rotary cam plate 18. Disposed in the center of the plate 18,as shown at 20, is a stub shaft 22 having a keyed outer portion 24adapted for driving connection with a suitable source of rotary power.

The cam plate 18 is provided with a ball channel 26 in which a series ofballs 28 are located. The balls are retained with the aid of acomplementary ball channel 30 in the input or outer side of a rotaryinput member or disc 32 having an outwardly directed flange 34containing a bearing ring 36 which rides upon the balls 28.

The input disc 32 has a peripheral sealing ring 38' which bears'againsta stationary containing ring 40, the

latter having a radial flange 42 connected by a series of bolts to theend plate 12.

The left-hand side of the rotary input disc 32 is provided with aconcave surface of revolution 46 which may approximate a toric section.

The structure is provided with a left-hand end plate 48 which issuitably connected by bolts 50 to an end ring 52 which lies in theleft-hand portion of a cylindrical casing member 54. The right-hand endplate 12 has its bolts 44 threaded into a connector ring 56 which issuitably connected as by welding to the right-hand end of thecylindrical casing 54.

The left-hand plate 48 supports a ball bearing assembly 58 which, inturn, rotatably supports an output or driven disc 60. The disc member 60is provided with a concave surface of revolution 62 which definesgenerally a toric section. Its profile may be approximately the same asthat of driving disc member 32.

Interposed between the driving and driven disc members 32 and 60 are aplurality of power-transmitting conically profiled rollers 64; eachroller having a convex surface of revolution 66. It is preferred thatthe conical profile surface 66 of the rollers 64 have a smaller radiusthan the profile surfaces 46 and 62 of the disc members 32 and 60.

The cam plate 18 and the driving disc member 32, with their ball grooves26 and 30, respectively, are so constructed that increased torque on thedrive shaft 22 will eifect an increased axial pressure on the drivingdisc member 32, urging it toward the driven disc member 60. The ballchannel 26 in the cam plate 18 is constructed similarly to the ballchannel 30 in the driving disc 32; the latter being illustrated indetail in Figures 4, 5, and 6. In Figure 6, it will be seen that thebottom of the channel 30 has alternating high spots 68 and low spots 70connected by inclined cam surfaces 72. When the cam plate 18 has torqueapplied thereto, the balls will tend to ride up the slanted cam surfaces72 on the cam plate, as well as those of the driving disc member 32,thereby increasing the pressure of the driving disc member 32, againstthe rollers 64 and through said rollers to the driven disc member 60.The rollers are so mounted on spherical pivot 76 and trunnion 82 thatthey are free to pivot on 76 and to move in the general direction of theaxes of the disc members so that substantially all of the force appliedto the rollers at their point of contact with the driving disc member istransmitted to their point of contact with the driven disc member. Whenthe torque is reduced, the balls 28 will tend to move toward low spots71) and thereby reduce the above-mentioned pressure. Preloading of thecam plate 18 toward the driving disc member 32 may be provided by meansof a Belleville-type dished pre-load spring 71.

The power-transmitting rollers 64 are each formed with an open centralportion mounting a ball bearing unit 72; the inner portion of whichcarries a bearing cup 74. Located in the cup is a large ball 76 and aplurality of considerably smaller ball bearings 78 which are placed inthe cup after the large ball 76 has been disposed therein so as to coverthe surface thereof and thereby provide multiple point contacttherewith. Extending into the open top of the cup 74 is a thrust member80, the radially inner end of which has a surface formed as a portion ofa sphere for contacting the small ball bearings 78. The upper portion ofthe thrust member 80 is formed with external threads in order that itmay be threadedly secured to a trunnion shaft 82, as shown in Figure 2.Cylindrical housings 86 are rigidly secured to the main housing member54. The ends of the trunnion shaft 82 extend through stationarypartitions 90 in the cylindrical housings 86 and are provided withadjusting nuts 92 by means of which the trunnion shaft may be shiftedlongitudinally to properly center the power-transmitting roller 64relative to the axis of rotation of the concave surfaces of revolutionof the driving and driven disc members 32 and 60. The ends of thetrunnion shaft 82 may be supported by needle bearings mounted incylinders 86.

Extending from each of the bearing cups 74 in the rollers 64 is a rolleractuating control or tilting arm 94 whose outer end is provided with aball 96 which is housed within a cylindrical housing 98 welded on theside of a control ring 100. The control ring 100 is coaxial with theinput and output discs 32 and 60, and is provided with externalperipheral teeth 102 which mesh with teeth on a pinion 104, which latterpinion is also engaged with a pinion 106 secured to the shaft of asuitable servomotor 108. This servomotor should be able to provide quickstarts and stops in combination with accurate stop ping position. Theservomotor mechanism is adapted to be controlled by means of a rotaryshaft 110 which extends upwardly through the cylindrical main housing 54and rigidly mounts a friction drive wheel 112, which drive wheel is inconstant engagement with the concave surface 62 of the driven discmember 60.

The preferred form of air cooling system is shown in Figures l, 2, and3, and includes an inlet 114 which communicates with a divided supplymanifold 116 extending downwardly about the casing 54. Air inlctapertures 118 and 120 are formed in the wall of the housing 54, to introduce air into conduits 122 which lead radially inwardly to a centralmanifold 124. The manifold 124 is open at both ends and is in flowcommunication with hollow hub portions 126 and 128 of the driving anddriven disc members 32 and 60, respectively. The manifold 124 isstationary and is in coaxial alignment with the hollow hubs of thedriving and driven disc members 32 and 60. Sealing rings 130 and 132 areinterposed between each end of the manifold and the respective hubs ofthe driving and driven disc members. Radially extending air passages 134and 136 connect the hollow hub portions 126 and 128 with the outerportions of the driving and driven disc members, which passages lieclosely adjacent their respective concave surfaces of. revolution 46 and62. Hence, the input and output disc members serve as integralcentrifugal pumps for creating a pressure differential that drawscooling air inwardly through conduits 122 and expel such air throughapertures 138 and 140, and no special air pumps or fans are required forefiicient cooling of the transmission. With this arrangement, thesesurfaces may be effectively air cooled. Air flowing through the passages134 and 136 is exhausted through the right-hand end plate 12 by means ofapertures 138 and apertures 140 formed in the left-hand end plate 48.

In Figure 7, there is disclosed a lubricating system and disc membercooling system which may be utilized in connection with a slightlydifferent general structural arrangement of the main casing. The casing144 is shown as having an integral left side wall 146 and a removableright side wall 148. The driving and driven disc members 32 and 60 aresubstantially identical to those shown in Figure l, as are thepower-transmitting rollers 64 and their component parts.

The lower portion of the casing 144 includes an oil inlet 150, the innerend of which conduit has an upwardly extending oil line 152 connectedthereto provided with oppositely extending cross-arm sections 154. Thesecrossarm sections 154 are provided with outlet apertures 156, and itwill be seen that the cross-arm sections extend into the hollow hubs ofthe driving and driven disc members 32 and 60. Radiating from the hollowhub portions are lubricant conduits 158 and 160 formed in disc members32 and 60. With this arrangement, the conduits 158 and 160 will convey acooling flow of oil in heat-trunsferring relationship with the discmembers at points adjacent the traction surface thereof so as todissipate the heat losses resulting from the contact between the rollersand the disc members. The cooling oil, however, is not permitted to flowover the engaging surfaces of the rollers and disc members whereby thedanger of a build-up of oil in front of the contacting rotary surfaces42, 62, and 66 of these elements is eliminated. Such a build-up isespecially to be avoided because of the comparatively large width ofthese contacting rotary surfaces, as will be discussed more fullyhereinafter.

A lubricant flow passage is formed by a space 162 between adjacent faceportions of the cam plate 18 and the driving disc member 32, permittingflow of lubricant to the thrust transmitting balls 28 and thenceoutwardly at the point 164 into a space 166 inside of the end plate ateach end of the housing 144. The right end plate 143 is provided with anoil drain outlet 168 leading to a suitable sump in an outer casing (notshown). The left end plate 146 defines an oil drain aperture 170 withthe lower edge of the driven disc member 60 to permit the lubricant toflow through an opening 172 into the sump or other receiving meansprovided therefor.

An oil passage 174 extends through the cam plate 18 adjacent its centralportion and communicates with a radial passage 176 so as to providelubricant for the ball bearing assembly 1.6 in which the cam plate 18 isrotatably mounted. When oil fiows through the ball bearing assembly 16,it is conducted through a small port 178 so as to communicate with theoil flow passage 162. A branch oil flow space 180 is defined between theouter portion of the bearing assembly 16 and a part of the camplate 18.This space 180 is continued as shown at 182 between an outer portion ofthe cam plate 18 and a flange 184 formed on a bearing assembly ring 186,which ring fits into a large central opening in the right end plate 148.A conventional lubrication arrangement may be provided for the rotarysupport of the driven disc member 61 including lubricant passages 188which provide oil for the bearing assembly 58. The lubricant inletconduit 15% includes a branch 190 provided with outlet apertures 192adapted to spray lubricant over the exterior of the servo motor 1%. Thislubricant drops into a suitable sump referred to above, but not shown inthe drawing.

It should be noted that the servo motor control shown in Figure 7differs somewhat from that shown in Figure l. The servo motor 198 inFigure 7 mounts a wheel 194 on its main shaft, which wheel is infrictional contact with a wheel 1.96 supported on a stub shaft 198; thelatter being carried by the left housing wall 146. The wheel 196 is infrictional drive contact with the peripheral edge of the driven discmember 69.

In both the embodiment of Figure l and that of Figure 7., an internallysplined sleeve 2% is shown coaxially mounted in the center of the drivenmember 60. This sleeve is adapted to be drivingly connected with aconstant speed unit which, in the case of an aircraft, may be analternator, although this specific use is, of course, not intended tolimit the application of the invention.

In Figures 1, 2, and 3, there is shown lubricating means which may beutilized in addition to that shown in Figure 7. A certain amount oflubricant is contained within the cylindrical casing 54. Located in thelower medial portion of the casing are capillary wicks 246 and 248 whichare adapted to conduct small amounts of lubricant upwardly from thebottom of the casing. As shown in Figure 2, the wick 246 extendsupwardly in two directions from the bottom of the housing 54 and thenceradially inwardly as shown in Figure 3, to extend partially around thehollow driving shaft 22. The wick 24% extends upwardly in the housing 54to wipe against the inner portion of the concave surface 46 on thedriving disc member 32. Similarly, a wick 250 extends from the lowerportion of the housing 54 to the outside of the internally keyed sleeve2% in the driven disc member 60. This wick-type oiling systemautomatically meters the relatively minor amount of oil required forlubrication of the traction surfaces of the rollers and disc members, aswell as the ball bearings, and limits the quantity of oil splashed ontothese traction surfaces. This system is particularly applicable to theform of transmis- 6 sion shown in Figure 1. It. should be noted that bythe ultilization of such wick-type oiling system, the need of a specialoil pump and the accessories therefor is eliminated.

It will be observed that the rollers 64 and the disc members are formedwith spirally extending grooves 242 and 244, respectively, on theircontacting surfaces. These grooves 242 and 244 serve to prevent theoccurrence of a power loss at high rotational speeds of the discs androllers resulting from the build-up of lubricant in front of thecontacting rotary surfaces 42, 62, and 66, of these elements. Withoutthis grooving such build-up of lubricant on these surfaces may form awedge which tends to effect the separation of the rollers relative tothe discs. When such grooving is utilized, however, the trappedlubricant has only to flow a short distance along the contactingsurfaces into a groove. It has been determined that the depth of thegrooves may be very shallow and in Figures 1, 2, 7, and 9, their size isexaggerated in the interest of clarity. Although this grooving is shownas having a spiral configuration in order that it may impart a pumpingaction to the lubricant, the grooves may instead be formed as aplurality of axiallyspaced circumferential grooves. Moreover, thegrooving may be formed on the rollers alone, while the contact faces ofthe disc member are made smooth. It should likewise be particularlynoted that although such grooving is especially adapted for use inconjunction with a transmission of the type disclosed herein, it mayalso find use in other applications involving rapidly rotatingcontacting rotary surfaces.

In Figure 8, there is illustrated a modified form of mounting for therollers 64. Each of these rollers 64 and bearing assemblies 72' aregenerally similar to those shown in Figure 1. The bearing assembly iscarried on a reduced portion of an upwardly convexly shaped bearingsupport 270, while a concave cup 274 is positioned above the bearingsupport. The position of the center of the radius of curvature of theconvexly shaped portion of the bearing support 276 and of the concaveportion of the cup 274 should be located on the axis of rotation ofroller 64 and should preferably lie in or near the plane containing thecenter of contact of this roller With the driving and driven discmembers 32 and 60. The bearing support 27% and the cup 274 confine aplurality of relatively small ball bearings 276. The cup 274- issupported by a threaded spindle 2'78 and may be mounted in the trunnionshaft 82 in the same manner as the first-described power-transmittingroller mounting. Preferably, however, the cup 274 and spindle 278 willbe made integral with the cross-arm 82.

In operation, the input shaft 22 is adapted to be connected to a rotarysource of power whereby it may rotate the cam plate 18 and driving discmember 32. R0- tation of the latter member effects a concurrent rotationof the rollers 64 and hence of the driven disc member 69. The latterdisc member in turn rotates the internally keyed sleeve 2% so as todrive an aircraft alternator, or the like. For effective use, such analternator must be driven at a substantially constant speed. It iscontemplated that so long as the driven disc member 60 rotates at aconstant speed, the servo motor will remain stationary. If, however, thedriven disc member 6% has its speed of rotation reduced, the servomotormechanism will operate to partially rotate the control ring and thusshift the roller actuating control arms 94. This in turn causes atilting of each of the rollers 64 about an axis in a plane containingthe axes of rotation of the driving and driven disc members 32 and 69,said axis passing through the center of the contact of each roller withthe. driving disc and the center of contact of the roller with thedriven disc. The transmission shown in Figure l is adapted for acounterclockwise direction of rotation of its input shaft 22 when viewedfrom the front 7 or input side thereof. If the roller actuating arms 94are raised from the position of Figure 1, it will cause the rollers 64to move in a spiral direction relative to the profiles of the concavefriction surfaces 46 and 62 on the disc toward the dotted line position252 of Figure l. The rollers 64 will each ride outwardly on the con cavesurface of the driving disc member 32 and inwardly on the concavesurface of the driven disc member 60 during such movement. During thismovement of the rollers, the loads carried thereby continue to becarried by the trunnion shafts 82, these shafts rotating about theirlongitudinal axes within the bearings mounted in the fixed cylinders 86.This will increase the speed of the output member 60 until it has againreached the proper speed. It should be noted that raising of the controlarms 94 as described hcreinabove serves to shift the axis of rotation ofeach of the rollers 64 whereby they no longer intersect the axis ofrotation of the disc members 32 and 60. The control arms thus steer therollers 64 from one ratio position to a new ratio position. When therollers reach the new ratio position their individual axes of rotationwill again automatically intersect that of the disc members. During thetime the rollers are moving bodily to their new ratio positions thecontact path of each of the rollers 64 actually spiral when their angleis being changed. The fact that the rollers 64 actually spiral to a newposition, rather than merely skid to a new position, provides verydefinite advantages, since a minimum loss of traction takes place duringsuch roller movement. of the rollers is required, less wear of thevarious parts of the device will take place, a high etiiciency may beobtained because of the low heat loss, and the size of the transmissionmay be small as compared to its capacity. Furthermore, a minimum amountof control force need be utilized whereby the size and weight of thecontrol mechanism may be kept small.

When the roller actuating control arms 94 are each tilted as mentioned,the relative arrangement of each arm to the ball 76 in the roller cup 74and also relative to the roller trunnion shaft 82 is such that for apredetermined degree of tilt of the control arm 94, each roller 64 willmove to a definite ratio position and reach a point of equilibrium in aplant normal to the axis of the roller thrust member 80, that is, withits axis of rotation intersecting that of the disc members. As a result,it will be seen that the device will act promptly and accurately inresponse to movement of the servo motor mechanism and that thismechanism will move in response to fluctuations in speed of the drivendisc member 60. Although the rollers 64 have shown and described asbeing provided with a pivot in their center on an axis which passesthrough the center of contact of each roller with both disc members, itshould be noted that the rollers can be caused to spiral from one ratioposition to another even if this pivot center is disposed above or belowthis axis. The advantage of having the axis pass through the center ofcontact of the roller with the disc members is that the traction forceswill have no moment arm through which a reaction with the control systemcould occur. In certain instances, however, it may be desirable tolocate the pivot axis above or below this axis, in order to effect anautomatic control of the ratio position responsive to a predeterminedtraction force action on the rollers. Such traction forces would tend torotate the control ring 109, which rotation could be resisted byresilient means such as a spring or hydraulic piston-cylinder devicewhereby the ratio position would be controlled by the traction force onthe rollers.

During operation, assuming the driven sleeve 200 is connected to adevice such as an alternator, if a sudden increase in the power loadoccurs, it will require that an increase in torque be supplied by thepower source to the input shaft 22. Under such conditions, the cam plate18 will tend to rotate relative to the driving disc member Accordingly,minimum loading 32, causing the cam balls 28 to ride up the incline 72in their ball grooves 26 and 30, and impart a greater axial thrust onthe disc member 32. This creates greater compressive forces between thedriving and driven disc members 32 and 60 relative to the convex surface66 of each roller 64 to permit each roller to transmit the increase intraction force required by the additional torque without slip at thetraction surfaces. When the power load returns to normal, the torqueinput may be reduced to normal again so that there is then a reducedthrust imparted by the cam plate 18 whereby the cam balls 28 may rolldown the incline 72 and thus impart a reduced axial thrust on drivingdisc member 32. This serves to reduce the compressive forces between therollers 64 and the disc members 32 and 60 so as to improve the overallefficiency of the device at part load and to permit its parts to have alonger service life.

In this regard, it should be particularly noted that the radius of theprofile surface 66 of each roller 64 is less than the radius of theprofile surfaces 46 and 62 of the disc members 32 and 60. Accordingly,during such part load conditions, the contact path between the rollersand the discs is relatively much narrower than when under full powerload, and hence the departures from true rolling which occur in thecontact path and which produce a certain amount of friction power lossand some heat are considerably reduced over that for full power.Additionally, since this contact path is narrower at part load, thepower loss resulting from the build-up of oil in front of the contactingrotary surfaces 42, 62 and 66 will be less than at full load. Since thisis true, wear between these surfaces will be at a minimum. Under full ornear-full load conditions, however, it has been determined that theroller surfaces 66 will actually deform so as to approximate thecurvature of the disc surfaces 46 and 62 by virtue of the increasedaxial thrust imparted upon the driving disc 32. Because of suchdeformation, it would be undesirable to have the radius of the profilesurface 66 of the rollers 64 equal to the radius of the profile surfaces46 and 62 of the disc members 32 and 60. This is true since even veryslight deflection of these parts under an increase in load and/or adifferential temperature expansion could cause the contact of theseveral rollers with the disc members to occur at different points onthe disc member Additionally, the contact point of an individual rollercould exist at different points on each disc member. The elfect of suchconditions would be an increased power loss, increased stress, andindefinite control over the rollers. The practical difliculty ofmachining and fabricating the transmission if these radii were equal,will also be evident.

Referring now to Figures 9 through 17, there is shown another form oftransmission embodying the present invention, which transmission broadlycomprises a cylindrical casing 250 wherein are mounted an input shaft252 adapted to rotate an input disc member 254, an output shaft 267adapted to be rotated by an output disc member 258, and a plurality ofpower-transmitting conically profiled rollers 260 having a convexsurface of revolution 262. The radius of the surface 262 of each rolleris less than the radius of the profile surfaces 264 and 266 of the discmembers 254 and 258, respectively. The output or driven shaft 256 isformed with splines 268 for receiving the shaft of an aircraftalternator, or the like (not shown). Each of the rollers 269 issupported by a trunnion shaft 270 that is rotatable about itslongitudinal axis when the roller is tilted by means of a tilting arm272. The tilting of these arms is in turn effected by a control ringwhich is connected to cylindrical housings 98 and to a servornotor (notshown) in the same manner as set forth with regard to the transmissionshown in Figure l or in Figure 7. It i contemplated, however, that othertypes of speed-sensing mechanisms may be utilized for controlling theeontrol ring 100.

As shown in Figure 11, the ends of the trunnion shafts 270 are disposedwithin fixed cylinders 276 and needle bearings 278 permit relativerotation therebetween. Adjustment of the shaft 274 with respect to thesecylinders 276 may be effected by means of a pair of pusher elements 279coaxially slidably carried within these cylinders, such pusher elementsincluding threaded rods 280 supported within rings 282 and mounting locknut 284. The midportion of each trunnion shaft 270 is formed with a boreat 236 to slidably receive the outer end of a thrust member 288. Anadjustment stud and nut combination 2% is mounted by each trunnion shaftfor obtaining the proper adjustment of the thrust member 288 relativethereto.

Referring to Figure 12, the thrust member 283 is coaxially disposedwithin a thrust cup 292, which cup is in turn coaxially encircled by theroller 260. The radially inner end of the thrust member 288 is formedwith a flange 234 having spherically curved sides 296 adapted to bearagainst radially inner side wall 298 of the thrust cup 292. The radiallyinner end of the thrust member is formed with a cavity 300 having agenerally flat end wall 392. A pivot element 304 is disposed against theend wall 306 of the cup 292 so that its center portion 398 may bearagainst the end wall 302. This center portion 398 is spherically curvedas indicated at 310 whereby there is provided a substantiallyfrictionless pivot point between the thrust member 288 and the thrustcup 292. With this arrangement, during movement of the tilting arms 272to change the ratio position of the rollers 26%, the thrust cups 292,and hence the rollers 269 may undergo pivotal movement independently ofthe thrust members 288. In this manner, the rollers 260 are free tospiral to their new position even though the required amount of radiallyinwardly directed force is being applied thereto by means of the thrustmembers 288.

As indicated in Figure 13, only the rollers 260 are formed with oilrelief grooves 242 in this form of the invention, the contact faces ofthe input and output disc members being smooth.

As shown in Figure 9, the rollers 260 are rotatably supported by a pairof axial thrust type ball bearings 31%, the inner peripheries of whichencircle the thrust cups 292. The outer portion of each thrust cup isformed with a spirally curved groove 312, whereby an oil conductingpassage 313 is defined when the ball bearings and thrust cups areassembled. The lower end of this passage 313 is connected to the insideof the thrust cup below the thrust member flange 294 by a short bore314. This portion of the thrust cup cavity is in turn in communicationwith an axial bore 316 extending through the thrust member 288 byauxiliary bores 318. Referring to Figure 11, the thrust members axialbore 316 receives oil by means of a cavity 318 formed in one side of thetrunnion shaft 279 and transverse bores 320 formed in the thrust member;the cavity 318 being connected by a branch to oil line 334. O-rings 324,326, and 328 may be provided for sealing the circulated oil.

The oil entering the lower end of the passage 313 will be urged radiallyoutwardly therethrc-ugh during operation of the device. The upper oropposite end of passage 313 empties into a passage 330 formed throughthe center of the tilting arm 272. This latter passage 330 empties intothe main housing out of communication with the roller path. The oil line334 encircles the interior of the casing 250 and receives oil underpressure from an oil pump (not shown) mounted at the bottom of thecasing and driven by the shaft 274. With this arrangement, the bearings310 may be provided with a cooling agent that follows a closed path andhence will not come into contact with the contact surfaces of therollers and the disc members. The oil circulated through the casing maybe cooled by contact with the upper cooling fins 336, such oil beingconducted thereto by a manifold member 338, as shown 10 in Figure 9. Atachometer 346 driven by a shaft 342 is shown mounted at one side of thecasing 250.

Referring again to Figure 9, the front end of the casing 25% is formedwith a bore 344 wherein is mounted a bearing retainer cup 346, which cupin turn receives the outer race of a front ball bearing 348. The outerperiphery of this cup 346 may be supplied with a cooling fluid, such asoil, by means of a conduit 350. The inner race of the ball bearing 348encircles the front portion of a drive sleeve member 360, which lattermember is formed with a blind bore 362. A plurality of freewheelingsprag elements 364 are circumferentially arranged within the annularspace separating the inner periphery of the blind bore 362 and the outersurface of the input shaft 252. These sprags are retained in thisannular space by snap rings 365 and 366. The rear portion of the drivesleeve member 360 is of larger diameter than the front portion thereofand is formed with multiple spiral grooves defining a double thread 368.The input disc member 254 is formed with a complementary multiple spiralgroove defining a double thread 370 whereby there is defined a spiralball channel 372 wherein are disposed a plurality of balls 374.

As shown in Figures 14 through 16, the starting point of one thread ofthe double thread 370 is joined to the end of the other thread by across-over notch 376 which is in part defined by a pair of scoopingfingers 378. These scooping fingers 378 may consist of curved rods thatare secured to the input disc member 254 by means of bolts or screws380. With this arrangement, if the input shaft 252 and hence the drivesleeve member 369 is rotated in a counterclockwise direction when viewedfrom the front, the balls 374 will also tend to roll in the channel 372in a counterclockwise direction until they reach the cross-over notch376. Since, as shown in Figure 16, this notch is deeper than theremainder of the ball channel 372 formed in the input disc member 254,the balls will roll outwardly sufliciently to be able to move up overthe rib 382 between the two threads of the double lead thread 370whereby they will be free to recirculate through the channel. Duringmovement of the balls through the cross-over notch 376, the scoopingfingers 378 provide a surface having a gentle curvature for guiding theballs through the notch. The ends of the scooping fingers may extendover the ends of the cross-over notch. The balls 374 will be free tocontinue to move slowly or walk around the ball channel 372 as long asthe input shaft 252 is being rotated. Hence, these balls will not remainin any one position for an appreciable period of time, and accordinglythey will not cause pitting of the walls of the ball channel duringnormal operation. If a sudden above normal load is imposed upon thealternator (and hence the driven disc member 253) whereby an increase intorque must be applied to the driving disc member 254, the balls willroll between the grooves 368 and 370 so as to screw the driving discmember to the left so as to increase the pressure of the driving discmember against the rollers 26%) and through said roliers to the drivendisc member 258. inasmuch as the balls travel through the channel 372with a random movement, there is little chance they will be disposed atthe same given spot therein for any suddenly applied, above normal load.Hence, these balls will not cause a pitting of the walls of the channelwhen a sudden load is applied. A flexible, dished disc-type spring 385provides pre-loading of the drive sleeve member 3617 toward the inputdisc member 254, as shown in Figure 9. With the aforedescribedarrangement, a single ring of balls 374 may be employed. This is madepossible by the use of a double-lead thread in the spiral channel 372.

Referring now to Figures 18 and 19, there is shown another form oftorque varying means which may be utilized with a transmissionconstructed in accordance with the present invention in place of thoseshown and described hereinabove. This torque varying means is of anangular contact cam type and includes a drive sleeve member 386 which isadapted to be coupled to the input shaft 252 of a transmission such asthat shown in Figures 9 through 16 in the same manner as the drivesleeve member 360 described above. The rear portion of the drive sleevemember 386 defines a smooth inner raceway 388 for a plurality of balls390 carried by a retainer 392. The outer raceway 394 for such balls isformed at the front portion of the driven disc member 254'. This outerraceway 394 includes a plurality of peel-Lets defining cam surfaces 396which are inclined axially toward the driven disc member (not shown). inoperation, upon the application of torque above that which will fullycompress a pre-load spring, such as that designated 335 in Figure 9, theballs will tend to cam the input disc member to the left so as toincrease the pressure of the input disc member 254 against the rollers(not shown) and through the rollers to the driven disc member (notshown). It should be particularly observed that the balls 390continually move. or walk, relative to the smooth inner raceway 388during operation of the transmission. Accordingly, the danger of theballs causing a pitting of this raceway is minimized. Although the outerraceway 394 may become slightly worn by the balls, such wear is spreadover a greater are than would be the case with the inner raceway.Furthermore, the contact stress of the balls will be lower on the outerraceway than on the inner raceway.

it will be understood that various modifications and changes may be madewith respect to the foregoing detailed description without departingfrom the spirit of the invention or the scope of the following claims.

This is a continuation-in-part of application Serial No. 175,695,bearing the same title and filed by me July 24, 1950, now abandoned.

I claim:

l. in a transmission, having a frame that rotatably mounts a pair ofopposed axially-spaced coaxial driving and driven disc members: aconically profiled roller bridging said disc members; a thrust cupforming the shaft of said roller and having its open end facing radiallyoutwardly; a thrust member connected at an end to said frame and havingits radially inner end disposed within said cup; :1 bearing encirclingsaid cup, the outer portion of said roller rotating about said bearing;a control arm rigidly secured to the upper portion of said cup foreffecting tilting thereof; an axially extending bore formed through saidthrust member; a groove formed in the outer portion of said cup andextending axially therealong; means for conducting a cooling fluid tothe radially outer portion of the bore formed in said thrust member;and. a passage formed through said arm and connected to said groovewhereby a cooling fluid may be forced through said bore, groove andpassage without contacting said members.

2. A transmission comprising: a frame; a driving shaft rotatably mountedby said frame; a driving disc member coaxially mounted by said shaft; acoaxial driven disc member rotatably mounted by said frame opposite toand axially spaced from said driving disc member; a roller interposedbetween said disc members in rotationtransmitting contact therewith; atrunnion shaft mounted by said frame; a thrust member extending inwardlyfrom said trunnion shaft in a plane extending through the axis ofrotation of said disc members; a thrust cup forming the shaft of saidroller and having its open end facin said trunnion shaft; a pivotelement disposed in the lower end of said cup in pivotal abutment withinner end of said thrust member; a bearing encircling said cup, theouter portion of said roller rotating about said bearing; a control armrigidly secured to the upper portion of said cup for effecting tiltingthereof; an axially extending bore formed through said thrust member; aspirally curved groove formed in the outer portion of said cup, saidbore and said groove being in communication; a cavity formed in saidtrunnion shaft and connected with said bore; and, a passage formedthrough said arm and connected to said graave whereby a cooling fluidmay be forced through said cavity, bore, groove and passage.

3. A transmission comprising: a frame; a driving shaft rotatably mountedby said frame; a driving disc member coaxially mounted by said shaft,said disc being movable axially relative to said shaft; a coaxial drivendisc member rotatably mounted by said frame, said disc members havingopposed axially-spaced concave surfaces of revolution approximating atoric section; a roller interposed between said disc members and havinga convex surface of revolution in bridging contact with the concavesurfaces thereof; a trunnion shaft mounted by said frame; a thrustmember extending inwardly from said trunnion shaft in a plane extendingthrough the axis of rotation of said disc members; a thrust cup formingthe shaft of said roller and having its open end facing said trunnionshaft; a pivot element disposed in the lower end of said cup in pivotalabutment with the inner end of said thrust member; a bearing encirclingsaid cup, the outer portion of said roller rotating about said bearing;a control arm rigidly secured to the upper portion of said cup foretfecting tilting thereof; an axially extending bore formed through saidthrust member; a spirally curved groove formed in the outer portion ofsaid cup, said bore and said groove being in communication; a cavityformed in said trunnion shaft and connected with said bore; and, apassage formed through said arm and connected to said groove whereby acooling fluid may be forced through said cavity, bore, groove andpassage.

4. A transmission comprising; a frame; a driving shaft rotatably mountedby said frame; a driving disc member coaxially mounted by said shaft,said disc being movable axially relative to said shaft; a coaxial drivendisc member rotatably mounted by said frame, said disc members havingopposed axially-spaced concave surfaces of revolution approximating atoric section; a roller interposed between said disc members and havinga convex surface of revolution in bridging contact with the concavesurfaces thereof; a trunnion shaft mounted by said frame; a thrustmember extending inwardly from said trunnion shaft in a plane extendingthrough the axis of rotation of said disc members, the inner end thereofbeing formed with a flange having spherically curved sides; a thrust cupforming the shaft of said roller and having its cavity facing saidtrunnion shaft; and, a pivot element on the end wall of said cup, theinner end of said thrust member and the outer surface of said pivotelement bearing against each other and permitting pivot action betweensaid thrust member and said cup in all directions.

5. A transmission, comprising: a frame; a driving shaft rotatablymounted by said frame; a driving disc member coaxialy mounted by saidshaft, said disc being movable axially relative to said shaft; a coaxialdriven disc member rotatably mounted by said frame, said disc membershaving opposed axially-spaced concave surfaces of revolutionapproximating a torie section; a roller intel-posed between said discmembers and having a convex surface of revolution in bridging contactwith the concave surfaces thereof; a trunnion shaft mounted by saidframe; a thrust member extending inwardly from said trunnion shaft in aplane extending through the axis of rotation of said disc members, theinner end thereof being formed with a flange having spherically curvedsides; a thrust cup forming the shaft of said roller and having itscavity facing said trunnion shaft; and a pivot element disposed againstthe end wall of said cup, said element being formed with a sphericallycurved surface that bears against the flat inner end of said thrustmember, the spherically curved sides of said flange bearing against theinner side walls of the cavity of said cup whereby said cup may pivotfreely relative to said thrust member.

6. A transmission comprising: a frame; a pair of in dependentlyrotatable coaxial driving and driven disc members formed withspaced-apart opposed concave surfaces of revolution approximating atoric section; a conically profiled roller interposed between said discmembers formed with a convex surface bridging the concave surfacesthereof; mounting means between said frame and said roller normallysupporting said roller with its axis of rotation intersecting the axisof rotation of said disc members, said mounting means including auniversal mounting for the roller and a tiltable member supporting saiduniversal mounting; said control means independent of said mountingmeans for shifting the axis of rotation of said roller so that it nolonger intersects the axis of rotation of said disc members inpreparation for a change to a new ratio position wherein said axes willagain intersect, said mounting means permitting said control means tosteer said roller to said new ratio position, said roller moving bodilyto said new ratio position with its surface in contact with the surfacesof said disc members undergoing substantially skid-free rolling movementin a spiral path along the latter surfaces.

7. A transmission comprising; a frame; a pair of independently rotatablecoaxial driving and driven disc members formed with spaced-apart opposedconcave surfaces of revolution approximating a toric section; aconically profiled roller interposed between said disc members formedwith a convex surface bridging the concave surfaces thereof; mountingmeans between said frame and said roller normally supporting said rollerwith its axis of rotation intersecting the axis of rotation of said discmembers, said mounting means including a universal mounting for theroller and a tiltable member supporting said universal mounting; andcontrol means independent of said mounting means for shifting the axisof rotation of said roller so that it no longer intersects the axis ofrotation of said disc members in preparation for a change to a new ratioposition wherein said axes Will again intersect, said mounting meanspermitting said con-- trol means to steer said roller to said new ratioposition, said roller moving bodily to said new ratio position throughan are having a center contained in a plane extending through the axisof rotation of said disc members and coinciding with the center ofcurvature of the profile surfaces of said disc members at said plane,the surface of said roller in contact with the surfaces of said discmembers undergoing substantially skid-free rolling movement in a spiralpath along the latter surfaces.

8. A transmission comprising: a frame; a pair of independently rotatablecoaxial driving and driven disc members formed with spaced-apart opposedconcave surfaces of revolution approximating a toric section; aconically profiled roller interposed between said disc members formedwith a convex surface bridging the concave surfaces thereof; mountingmeans between said frame and said roller normally supporting said rollerwith its axis of rotation intersecting the axis of rotation of said discmembers, said mounting means including a universal mounting for theroller and a tiltable member supporting said universal mounting, thecenter of said universal mounting substantially coinciding with a linepassing through the center of contact of said roller and disc members;and control means independent of said mounting means for shifting theaxis of rotation of said roller so that it no longer intersects the axisof rotation of said disc members in preparation for a change to a newratio position wherein said axes will again intersect, said mountingmeans permitting said control means to steer said roller to said newratio position, said roller moving bodily to said new ratio positionwith its surface in contact with the surfaces of said disc membersundergoing substantially skid-free rolling movement in a spiral pathalong the latter surfaces.

9. A transmission comprising; a frame; a pair of independently rotatablecoaxial driving and driven disc members formed with spaced-apart opposedconcave surfaces of revolution approximating a toric section; aconically profiled roller interposed between said disc members formedwith a convex surface bridging the concave surfaces thereof; mountingmeans between said frame and said roller normally supporting said rollerwith its axis of rotation intersecting the axis of rotation of said discmembers, said mounting means including a universal mounting for theroller and a tiltable member supporting said universal mounting, saidtiltable member having a thrust element formed with a trunnionpermitting said thrust element to tilt in a plane extending through theaxis of rotation of said disc members, the axis of said trunnion beingnormal to said plane and extending through the center of curvature ofthe profile surfaces of said disc members at said plane; and controlmeans independent of said mounting means for shifting the axis ofrotation of said roller so that it no longer intersects the axis ofrotation of said disc members in preparation for a change to a new ratioposition wherein said axes will again intersect, said mounting meanspermitting said control means to steer said roller to said new ratioposition, said roller moving bodily to said new ratio position with itssurface in contact with the surfaces of said disc members undergoingsubstantially skid-free rolling movement in a spiral path along thelatter surfaces.

10. A transmission comprising: a frame; a pair of independentlyrotatable coaxial driving and driven disc members formed withspaced-apart opposed concave surfaces of revolution approximating atoric section; a conically profiled roller interposed between said discmembers formed with a convex surface bridging the concave surfacesthereof; mounting means between said frame and said roller normallysupporting said roller with its axis of rotation intersecting the axisof rotation of said disc members, said mounting means including auniversal mounting for the roller and a tiltable member supporting saiduniversal mounting, said tiltable member having a thrust element formedwith a trunnion permitting said thrust element to tilt in a planeextending through the axis of rotation of said disc members, the axis ofsaid trunnion being normal to said plane and extending through thecenter of curvature of the profile surfaces of said disc members at saidplane, the center of said universal mounting substantially coincidingwith a line passing through the center of contact of said roller andsaid disc members; and control means independent of said mounting meansfor shifting the axis of rotation of said roller so that it no longerintersects the axis of rotation of said disc members in preparation fora change to a new ratio position wherein said axes will again intersect,said mounting means permitting said control means to steer said rollerto said new ratio position, said roller moving bodily to said new ratioposition with its surface in contact with the surfaces of said discmembers undergoing substantial skid-free rolling movement in a spiralpath along the latter surfaces.

11. A transmission as set forth in claim 10 wherein said thrust elementhas a thrust-receiving free end, and said roller has a thrust-impartingelement pivotally engaging said thrust-receiving free end.

References Cited in the file of this patent UNITED STATES PATENTS1,033,991 Cotoli July 30, 1912 1,774,176 Erban Aug. 26, 1930 1,775,479Arter Sept. 9, 1930 1,813,957 Robertson July 14, 1931 1,979,170 NardoneOct. 30, 1934 1,981,910 Ehrlich Nov. 27, 1934 2,076,560 Hayes Apr. 13,1937 FOREIGN PATENTS 22,188 Great Britain Jan. 27, 1900 673,168 GreatBritain June 4, 1952

